Often, a call may go through several service provider networks in order to connect from a calling party to a called party. Each service provider's network may include several domains (or administrative boundaries). In Time Division Multiplexed (TDM) Networks, resource clearance using signaling messages is supported through serial resource clearance on a link-by-link basis. In the serial (or sequential) case, no node transmits a message until first obtaining resource clearance within its domain. Accordingly, the total time required to set up a call or session with a link-by-link signaling method is O(Σti) where ti represents the time it takes for resource clearance in the i-th link.
Priority services is the name given to preferred treatment of certain kinds of traffic (e.g., media/data and signaling) over other kinds of traffic in, for example, the context of civilian or defense communication networks. Priority in a public switched telephone network (PSTN) is performed on a switch by switch basis. Calls for priority users, such as government entities pass through switches while non-priority traffic is blocked.
Three kinds of priority services exist as present; namely, wireless priority service (WPS), Government emergency telecommunications services (GETS) by national communications systems (NCS) and multi-level precedents preemption (MLPP) by the United States Department of Defense.
GETS provides an ability to preempt calls at a lower priority than MLPP. GETS also provides for buffer-type queuing of a call such that the call will be the first call to pass when a necessary resource becomes available. Call control functionality includes the decision of choosing which call to allow and which call to preempt. Resource control and policy-based management functionality includes the decision of when to preempt a call or when to buffer-type queue a call.
Within the context of voice, video and other data communications (e.g., multimedia communications and the like) via packet based networks (e.g., Ethernet, etc.) resource clearance is handled on a sequential basis. Methods for preemption and priority handling of voice calls and multimedia services are also lacking in packet based networks.
Summary of the Information
A network element, apparatus and method for combining call admission control and priority services within different type of networks is provided. A logical functional entity denoted as a Priority Services Functional Element (PSFE) enables administration of priority services and call or session admission control policies through interactions with Call Session Control Function Element (CSCF) and Resource Access Control Facilities (RACF). Method steps in exemplary embodiments may include verifying the priority levels, receiving resource availability information, storing call admission and resource allocation information, identifying path and link information required for an originated session, checking available resources at links against required, requested and sufficient resources for the call or session establishment, and communicating resource availability and sufficiency indication/s (or lack thereof) based on admission control policies after resource verification.
The PSFE allows for capacity and priority management in parallel over all the links in the bearer path within a particular network. PSFEs in different networks can also communicate to enable PSFEs in each network in the path to perform resource clearance independently and in parallel (i.e., undertaking apparent or actual performance of more than one operation at a same time). Proposed methods allow both kinds of parallelization in networks of different architectures, such as IMS and SIP, and also across varied networks. The PSFE introduces obtaining parallel resource clearance across network boundaries, including heterogeneous networks. In this manner, calls or sessions may be established efficiently, and varied features provided in a multi-media network.
PSFE may use Session Initiation Protocol (SIP) messages to communicate with Signaling and Service Layer entities, such as Proxy (P-) or Interrogating (I-) CSCFs, Subscriber Information Databases (e.g., Home Subscriber Server or HSS), and Application Servers (AS). PSFE may also communicate with Transport Layer entities (such as, RACF in an all IMP Multimedia Subsystems (IMS) architecture) using, for example, Diameter messages. However, PSFE may integrate both IMS and non-IMS Next Generation Service Provider (NGSP) networks and enable efficient resource verification and allocation in the non-IMS NGSP also. Further, the PSFE may also determine resource availability using open loop control or other accounting methods in a network without a RACF.
Parallel resource clearance is useful in establishing various multi-media services in all IP-based networks regardless of the types of users and may be utilized in Enterprise, Commercial Service Provider, Civilian Government, and Military network segments of IP networks. In context of priority services, such a PSFE can provide higher priority to priority service users and queue such users' requests for resources ahead of resource requests from other, routine users. Priority session requests and associated priority levels can be identified by the PSFE, for example, through Resource Priority Headers (RPH) in the SIP message. It is important to note that to queue priority sessions ahead of routine sessions, no routine session can be allowed in any of the links in the priority session path. Coordination of such activities across multiple network segments, which is quite complex among CSCFs, Back to Back user Agents (B2BUAs), and Session Border Controllers (SBCs) in separate network segments, can be achieved via communicating PSFEs deployed in these segments.
Next generation networks may offer various services with multi-media capabilities. For example, multi-media point-to-point communication or multimedia conferencing may be offered. Typically, the media used in multi-media communications has different bandwidth and performance requirements. For instance, video services require high bandwidth while data communications require lesser bandwidth in general. Further, a user may be able to use multi-media communications services separately or in combination as per the user need. For example, a user may share a whiteboard or net-meeting with another user exchanging data only or may talk between themselves at the same time or may even use real-time video communications. Multiple users may also participate similarly.
In normal conditions, the communication network has sufficient bandwidth to support any such combination of media services. However, networks may not have sufficient bandwidth during stressed times, which could occur due to environmental causes (e.g., earthquake, or tornado) or due to unintended human actions (e.g., fiber cut due to digging) or intentional and malicious human activities (e.g., hacking, virus, terrorism). Furthermore, networks in the communication path may be bandwidth constrained such as, wireless networks, or ad-hoc network segments as sometimes used in emergency or in tactical war environments. In such situations, there may not be sufficient bandwidth to initiate the full multi-media service suite. Nevertheless, it may be desirable and prudent to establish the services that can immediately be started based on available bandwidth and add the other services as soon as more bandwidth becomes available. A call-state aware functional element knowledgeable about transport resource usage is provided to enable resource usage assessment and procurement that permits such incremental resource addition.
Several different types of situations, e.g., user addition, media addition, and media quality and capability enhancement, can be addressed through such ad-hoc resource addition on availability. With user addition, users can be added subsequently when there is not sufficient bandwidth to add all desired participants at the start of a conference. For media addition, media types can be added incrementally when there is not sufficient bandwidth to support all media types requested in a call/session initially For media quality or capability enhancement, when there is not sufficient bandwidth to support higher quality and higher capability sessions of a particular media (video or voice) initially, the higher level media may be provided as resources become available subsequently. The resource availability may occur from time-to-time from various reasons, including but not limited to, termination of previously established calls or sessions; restoration of bandwidth through network management or operations processes; and roaming by a roaming user into a network that can provide higher bandwidth. An exemplary resource is bandwidth.
Apparatus and method are provided for capacity and priority management of a communications network for use in a system having a plurality of networks. An exemplary method includes receiving at a first network a notice of an intended communication to a called party network, wherein the intended communication requires a resource for supporting a streaming data protocol in each network between a calling party network and the called party network. The notice of an intended communication is forwarded to a second network and toward the called party network. In parallel with said forwarding, a determination of resource availability for the first network is initiated for the intended communication. The determination of resource availability for the first network is performed for the intended communication, wherein the determination is for a first resource for the first network; and resource sufficiency for the intended communication verified. For example, resource assessment of resources sufficient for the intended communication are not queried and reserved sequentially from calling to called party but query and reservation of sufficient resources occurs simultaneously or near simultaneously.
In one embodiment, performing for the intended communication the determination of resource availability for the first network includes querying the first resource for the first network for resource availability, and receiving a first indication of resource availability of the first resource for the first network. In another embodiment, verifying resource sufficiency for the intended communication includes determining for the intended communication whether a first indication of resource availability for the first resource is above a threshold. In one embodiment, the threshold value corresponds to a media type of the intended communication. In another, the threshold is prescribed by the notice of intended communication.
Verifying resource sufficiency for the intended communication may include reserving for the intended communication the first resource for the first network in the event the first resource has resource availability above a threshold. In that embodiment, the first resource may be reserved at a first level, the first level being greater than the threshold value and being a minimum of a level of available resource in first network and a level of resource reserved in the second network.
In another embodiment, verifying resource sufficiency for the intended communication may include receiving for the intended communication from the second network a second indication of resource sufficiency of a second resource for the second network. One embodiment may include forwarding a re-invite for the intended communication to the second network and toward the called party network in the event a first indication of resource availability of the first resource for the first network is above a threshold and the second indication signifies resource sufficiency, wherein the first network is the calling party network, thereby indicating resource sufficiency for a corresponding resource in each network from the calling party network to the called party network.
One embodiment may include forwarding a request to a transit network interposed the first network and the second network for verifying with the transit network a predetermined Service Level Agreement (SLA) and that the SLA assures at least one requirement of the intended communication; receiving resource availability information for the transit network; and forwarding a re-invite of the intended communication to the second network and toward the called party network in the event a first indication of resource availability of the first resource for the first network is above a threshold, the second indication indicates resource sufficiency and the resource availability information for the transit network is above the threshold, wherein the first network is the calling party network, thereby indicating resource sufficiency for a corresponding resource in each network from the calling party network to the called party network.
In the event of receipt of a ringing message, one embodiment may forward a lock message, the lock message instructing that the first resource for the first network is to be used. Another method embodiment may also include forwarding a corresponding resource sufficiency message based on the resource availability information for the first network and the resource sufficiency information for the second network indicating resource sufficiency for the intended communication. Forwarding a corresponding resource sufficiency message may include forwarding the corresponding resource sufficiency message within the first network or to a third network. The second network and the third network may be the same network. For example, the resource sufficiency message may be forwarded within the first network, fed-forward to the second network and fed-backward toward the calling party network.
In one embodiment, the determination of resource availability for the first network is via an open loop control; in another, an accounting based control is utilized. In one embodiment, the performing for the intended communication the determination of resource availability for the first network includes communicating with a resource access control function (RACF) to verify the resource availability information concerning the first network. An exemplary embodiment may also include forwarding at least one of a SDPReoffer message or a re-invitation message for the intended communication after verifying resource sufficiency for the intended communication.
In one embodiment, verifying resource sufficiency for the intended communication includes reserving the first resource if its resource availability is above a sufficiency threshold, and the method further includes receiving a ringing message and locking the first resource for the first network that was reserved in response to the ringing message. Another embodiment has a priority indicator included in the notice of intended communication such that, while verifying resource sufficiency for a first intended communication, verifying resource sufficiency for a second intended communication having a priority indicator less than or equal to a priority indicator for the first intended communication is prevented.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures.